The Collaborative International Dictionary of English v.0.48:
Rale \R[^a]le\ (r[aum]l), n. [F. r[^a]le. Cf. Rail the bird.] (Med.) An adventitious sound, usually of morbid origin, accompanying the normal respiratory sounds. See Rhonchus. [1913 Webster] Note: Various kinds are distinguished by pathologists; differing in intensity, as loud and small; in quality, as moist, dry, clicking, whistling, and sonorous; and in origin, as tracheal, pulmonary, and pleural. [1913 Webster]